Systems for providing audio guidance according to the related art include, for example, an on-vehicle navigation system disclosed in JP 8-124092A. In this on-vehicle navigation system, an intersection guidance control process is executed by a map display control unit such that the current position of a controlled vehicle detected by a current position detection process will be displayed on a map of the relevant region read from a map data storing unit and displayed on a CRT display device. Further, the intersection guidance control process is executed to read a dialect or foreign language stored in a language database memory. The control process controls speech synthesis such that speech in the dialect or foreign language will be output to provide guidance for a right or left turn at an intersection, an announcement of the name of a place toward which the vehicle is headed after the right or left turn, or an instruction on a device operation. Thus, the speech of audio guidance is adapted to the dialect or language spoken in the region or country where the vehicle is traveling.
However, this on-vehicle navigation apparatus is required to have a storage device to store audio information in dialects spoken in various regions of a country or major languages in the world. Thus a storage device having an increased storage capacity results in an increase in the cost of the apparatus.